THIS ITEM IS FOR STORE PICK-UP ONLY. One cylinder of 14.5 oz CO2 (Sodastream's standard size), fitting all soda machines. It is rated to make approximately 60 liters of bubbly water. Just bring in your empty canister and trade it / "Exchange" it for a full one. If you don't have an empty cylinder you can purchase a "Spare" cylinder if you need an extra without having an empty to exchange. At checkout, under "Delivery Method", please select "Pick-up" tab, this is a free service. Or, call to place a phone order at 978-263-1955.